Method and system for rebuilding data following a disk failure within a raid storage system

Abstract

A method and system for rebuilding data following a disk failure within a RAID storage system. The rebuild process keeps track of the relative number of READ operations across a RAID group so that following a RAID disk failure, the most frequently read areas of the RAID group can be rebuilt before less frequently accessed areas. Host READs to the rebuilt area will no longer necessitate on-the-fly rebuild from parity data, and thus host performance will be much less impacted than with prior rebuild processes.

What is claimed is: 
     
         1 . A computer-implemented method for rebuilding data following a disk failure within a RAID storage system, wherein data is stored in a plurality of RAID sections distributed across a plurality of data storage devices, the method comprising the steps of:
 maintaining, by a processor, a record of I/O activity to each one of said plurality of RAID sections within said RAID storage system;   following a failure of one of said plurality of data storage devices, creating, by said processor, from said record of I/O activity, an optimized rebuild sequence comprising an identification of RAID sections prioritized according to RAID section I/O activity; and   rebuilding, by said processor, the RAID sections residing on said failed data storage device to a replacement data storage device in accordance with said optimized rebuild sequence.   
     
     
         2 . The computer-implemented method for rebuilding data following a disk failure within a RAID storage system in accordance with  claim 1 , wherein said RAID storage system comprises one of the following:
 A RAID 3 storage system;   A RAID 5 storage system, and   A RAID 6 storage system.   
     
     
         3 . The computer-implemented method for rebuilding data following a disk failure within a RAID storage system in accordance with  claim 1 , wherein said RAID sections comprise logical block addresses (LBAs). 
     
     
         4 . The computer-implemented method for rebuilding data following a disk failure within a RAID storage system in accordance with  claim 1 , wherein said I/O activity comprises read operations. 
     
     
         5 . The computer-implemented method for rebuilding data following a disk failure within a RAID storage system in accordance with  claim 1 , wherein said optimized rebuild sequence comprises an identification of RAID sections ordered by highest to lowest RAID section I/O activity. 
     
     
         6 . The computer-implemented method for rebuilding data following a disk failure within a RAID storage system in accordance with  claim 1 , wherein:
 said record of I/O activity to each one of said plurality of RAID sections includes a record of recent I/O activity to each one of said plurality of RAID sections; and   said optimized rebuild sequence comprises an identification of RAID sections prioritized according to RAID section I/O activity including application of a weighting factor to said recent RAID section I/O activity.   
     
     
         7 . A computer system comprising:
 a RAID storage system, wherein data is stored in a plurality of RAID sections distributed across a plurality of data storage devices; and   a processor for:   maintaining a record of I/O activity to each one of said plurality of RAID sections within said RAID storage system;   following a failure of one of said plurality of data storage devices, creating from said record of I/O activity, an optimized rebuild sequence comprising an identification of RAID sections prioritized according to RAID section I/O activity; and   rebuilding the RAID sections residing on said failed data storage device to a replacement data storage device in accordance with said optimized rebuild sequence.   
     
     
         8 . The computer system in accordance with  claim 7 , wherein said RAID storage system comprises one of the following:
 A RAID 3 storage system;   A RAID 5 storage system, and   A RAID 6 storage system.   
     
     
         9 . The computer system in accordance with  claim 7 , wherein said RAID sections comprise logical block addresses (LBAs). 
     
     
         10 . The computer system in accordance with  claim 7 , wherein said I/O activity comprises a read operation. 
     
     
         11 . The computer system in accordance with  claim 7 , wherein said optimized rebuild sequence comprises an identification of RAID sections ordered by highest to lowest RAID section I/O activity. 
     
     
         12 . The computer system in accordance with  claim 7 , wherein:
 said record of I/O activity to each one of said plurality of RAID sections includes a record of recent I/O activity to each one of said plurality of RAID sections; and   said optimized rebuild sequence comprises an identification of RAID sections prioritized according to RAID section I/O activity including application of a weighting factor to said recent RAID section I/O activity.   
     
     
         13 . A non-transitory computer-readable medium having a computer program for rebuilding data following a disk failure within a RAID storage system, wherein data is stored in a plurality of RAID sections distributed across a plurality of data storage devices, the computer program including executable instructions that cause a processor to:
 maintain a record of I/O activity to each one of said plurality of RAID sections within said RAID storage system;   following a failure of one of said plurality of data storage devices, create from said record of I/O activity, an optimized rebuild sequence comprising an identification of RAID sections prioritized according to RAID section I/O activity; and   rebuild the RAID sections residing on said failed data storage device to a replacement data storage device in accordance with said optimized rebuild sequence.   
     
     
         14 . The non-transitory computer-readable medium having a computer program for rebuilding data following a disk failure within a RAID storage system in accordance with  claim 13 , wherein said RAID storage system comprises one of the following:
 A RAID 3 storage system;   A RAID 5 storage system, and   A RAID 6 storage system.   
     
     
         15 . The non-transitory computer-readable medium having a computer program for rebuilding data following a disk failure within a RAID storage system in accordance with  claim 13 , wherein said RAID sections comprise logical block addresses (LBAs). 
     
     
         16 . The non-transitory computer-readable medium having a computer program for rebuilding data following a disk failure within a RAID storage system in accordance with  claim 13 , wherein said I/O activity comprises a read operation. 
     
     
         17 . The non-transitory computer-readable medium having a computer program for rebuilding data following a disk failure within a RAID storage system in accordance with  claim 13 , wherein said optimized rebuild sequence comprises an identification of RAID sections ordered by highest to lowest RAID section I/O activity. 
     
     
         18 . The non-transitory computer-readable medium having a computer program for rebuilding data following a disk failure within a RAID storage system in accordance with  claim 13 , wherein:
 said record of I/O activity to each one of said plurality of RAID sections includes a record of recent I/O activity to each one of said plurality of RAID sections; and   said optimized rebuild sequence comprises an identification of RAID sections prioritized according to RAID section I/O activity including application of a weighting factor to said recent RAID section I/O activity.